How does the infrared work?

[Guest Alex_le_brit]

am I right in thinking that the IR on the phone works by simply sending pulses of IR, and obviously receiving similar pulses? Or is it more complicated and there are changes of frequency of IR too?

Just wondering if it's related to the noises I mentioned in THIS thread.

[Guest markgamber]

am I right in thinking that the IR on the phone works by simply sending pulses of IR, and obviously receiving similar pulses? Or is it more complicated and there are changes of frequency of IR too?

Just wondering if it's related to the noises I mentioned in THIS thread.

<{POST_SNAPBACK}>

All IR devices either send, receive or send and receive a series of IR pulses which make up whatever data is being sent. The frequency of those pulses are up to the manufacturer but there are two "main" types of IR based on frequency and power. TV remote controls and such generally use a slow frequency and relatively high power output. They can be used from across the room but if you could see the beam, you'd notice the pulses because it's so slow. Digital devices like handhelds and the like, on the other hand, are far too fast to notice any distinct pulses but the beam is only good for a few inches. The common denominator is heat. As you increase frequency, you also increase temperature unless you lower the power. Conversely, if you increase power, you must lower the frequency or the temperature increases. Note that you don't automatically gain one by losing another. That is, lowering the frequency doesn't gain power by itself and vice versa. This is why most handhelds and all windows based phones that I'm aware of are not compatible with consumer devices and can't be hacked to make it so. Assuming you could write a device driver that would output slow IR pulses that would be compatible with consumer devices, the power would still be very limited and you couldn't use the device more than a very few inches from the television or whatever. To make it useful as probably defined by 99.99% of the public, you'd have to physically change circuitry to increase power and find a way to dissipate the generated heat.

Quick edit: I forgot that as you increase frequency and/or power output, you also increase draw on whatever source is powering the IR circuitry. Your battery suddenly lasting 1/4 of what it used to is not going to overjoy users, either.

Fun stuff, huh? :-) No one has to take my word for any of this. It takes little effort to run it through google and look this up yourself. And for those that will just have to argue with me here, don't bother. Talk is cheap, prove me wrong.

Edited February 18, 2005 by markgamber

[Guest Alex_le_brit]

Have no fear i'm not going to argue with you, really I'm wondering why it was that my phone clicked through the headset when I fired up the IR, and then that set me thinking, if all it is it on and off pulses, then it would be possible to capture the IR, process it so it was converted to high frequency sound, pick up the sound and convert that back to IR again.

Then again,we have bluetooth now, but you could really annoy your dog with it.

[Guest markgamber]

Have no fear i'm not going to argue with you, really I'm wondering why it was that my phone clicked through the headset when I fired up the IR, and then that set me thinking, if all it is it on and off pulses, then it would be possible to capture the IR, process it so it was converted to high frequency sound, pick up the sound and convert that back to IR again.

Then again,we have bluetooth now, but you could really annoy your dog with it.

<{POST_SNAPBACK}>

Bluetooth is much better than IR and that's what I'm interested in. Forcing a phone to half control a TV from three inches away is hardly what I'd call useful. Not even cool. Being able to control a bluetooth enabled TV using any kind of reasonable bluetooth device would be very cool.

[Guest Alex_le_brit]

Bluetooth is much better than IR and that's what I'm interested in. Forcing a phone to half control a TV from three inches away is hardly what I'd call useful. Not even cool. Being able to control a bluetooth enabled TV using any kind of reasonable bluetooth device would be very cool.

<{POST_SNAPBACK}>

But like I said, I'm not interested in TV Remotes, I have one, it came with the TV. I was more interested in how the IR worked for data transmission.

[Guest colinp]

u can see the infra red pulses if you point your phones camera at the infrared device :D

[Guest mavisdavis]

:D :shock: WOW I remember seeing this ages ago about the light caused through a camrea lens so I thought I'd give it a shot with my Sagem digi box remote. It even bouces off a matt painted wall. cool

Sorry abput the C500 photo it was taken with the wifes GD87 so its pretty pants ..Just like the C500 IR ;)

Edited March 1, 2005 by mavisdavis